docs: Add Component, GameObject, TransformComponent and Scene API documentation

- Add Component class documentation with lifecycle methods
- Add GameObject class documentation with component system
- Add TransformComponent documentation with transform methods
- Add Scene class documentation with GameObject management
- Add SceneManager singleton documentation with scene loading
- Update components.md overview with all component classes
- Update main.md navigation with Scene module

docs/api/components/game-object/add-component.md

@@ -0,0 +1,23 @@
+# GameObject::AddComponent
+
+向游戏对象添加组件。
+
+```cpp
+template<typename T, typename... Args>
+T* AddComponent(Args&&... args);
+```
+
+模板参数 T 必须继承自 Component。组件被添加后，其 m_gameObject 成员会自动设置为该 GameObject。
+
+**模板参数：**
+- `T` - 组件类型
+
+**参数：**
+- `args` - 传递给组件构造函数的参数
+
+**返回：** `T*` - 创建的组件指针
+
+## 相关文档
+
+- [GameObject 总览](game-object.md)
+- [Component](component/component.md)